It is known that in digital transmission it is possible to transmit data with different bitrate.
As an example, Internet provides users the possibility to watch videos stored on web servers. Since different users can have different type of connections to the network (e.g. wireless connection or cable connection or fibre optic connection), the web servers allow users to select the video quality, i.e. the bitrate, they can support. The higher the bitrate, the higher is the quality of the video, but the higher is the possibility of error transmission.
If data are transmitted with a TCP (Transmission Control Protocol) protocol, in case of error the data are sent again and the user only perceives a delay in the transmission or a not correct streaming.
If data are transmitted with an UDP (User Datagram Protocol) protocol, error transmission can be fatal since the receiver will not be able to reconstruct the correct order of the data stream.
Nowadays selection of the bitrate is accomplished with a traditional trial and error approach, wherein the user tries to setup communication with a first bitrate and then tries increasing or decreasing the bitrate until he finds the best compromise between quality and transmission errors.